1. Field of the Invention
The present invention relates to a method for changing a file name of a directory in a record medium having a plurality of data and a directory including file names of the data recorded thereon.
2. Related Background Art
A floppy disk or magnetic hard disk which magnetically records and reproduces data, and a card-like optical information record medium (optical card) or disk-like optical information record medium (optical disk) which records and reproduces data by using a light beam have been known as information record media. Auxiliary data or a so-called directory which manages data block by block to store a large volume of data is used in such an information record medium. Usually, file information such as file mames, file lengths and start data track numbers are recorded in the directory to manage the files of the data.
The optical card, particularly a non-erasable write-after type optical card has a size as small as a credit card but has a large record capacity. In order to manage such a large volume of information, the management of information by a directory is required.
FIG. 1 shows a plan view of an example of an optical card. The optical card 1 has a data record area 10 and a directory record area 20. A plurality of data are recorded on data tracks 10.sub.1, 10.sub.2, . . . , 10.sub.n of the data record area 10. On the other hand, a plurality of directories for managing the data are recorded in sectors 20.sub.1, 20.sub.2, 20.sub.3, . . . , 20.sub.n of the directory record area 20.
The data is sequentially recorded in an unrecorded area of the data record area 10 to follow the recorded data along a direction E. On the other hand, the directories are sequentially recorded in an unrecorded area of the directory record area 20 to follow the recorded directory along a direction D. A series of data are handled as a file and a directory is imparted to each file. The directory usually includes a file name of the data and address information such as a start track number.
When such a large volume of data is to be managed by files, it is desirable to erase unnecessary files in order to facilitate the retrieval of a desired file. However, in the write-after type record medium such as a conventional optical card, it is not possible to physically erase the recorded data.
A method for logically erasing unnecessary data by using the directory is provided in U.S. Pat. No. 4,910,724. This method is explained with reference to FIG. 2.
In FIG. 2, numerals 21 to 25 denote directory areas and numerals 21a to 24a denote data areas. Directory information of files 1 to 4 of the data areas 21a to 24a are recorded in directories 1 to 4 of the directory areas 21 to 24. Assuming now that the file 3 is no longer needed, an erasure directory 3 which indicates that the file 3 is not necessary is written into the directory area 25. In the erasure directory 3, the information which indicates that the directory is the erasure directory and the information which identifies the directory of the file to be erased are recorded. In the present example, the information of the directory 3 is recorded as the directory of the file to be erased. In this manner, the file 3 is logically erased.
When data is to be reproduced from the optical card, the data in the directory areas 21 to 25 is reproduced by an information recording/reproducing apparatus, and all or a necessary portion of the directory information of the directory areas, that is, the directory information of the directory areas 21 to 25 in the present example, are written into a memory in a host computer connected to the information recording/reproducing apparatus or an auxiliary memory. Then, the host computer erases the directory 3 indicated by the erasure directory 3 from the read-in directory information and writes the directories 1, 2 and 4. The files are managed by the directories 1, 2 and 4.
In the above method, the erasure directory for the file which cannot be actually erased is provided in the directory area so that the file is treated as if it were erased. By the use of the erasure directory, the updating of data of any file and the file name is attained. When the data is to be updated, the erasure directory is recorded, and the updated data and a directory which has the same file name and the address information of the updated data are recorded. In order to change the file name, the erasure directory is recorded and a new directory which has a new file name and the same address information such as the start data track number is recorded. This may also be applicable to the change of an attribution of the file.
On the other hand, Japanese Patent Application Laid-open No. 1-258288 discloses a method for appending data to a desired file. In this method, a flag (append flag) which indicates the addition of the file data is provided in the directory information. When the data is to be added to the file, the data to be added is recorded as a separate file. A directory which manages the additional data file (partial file) is recorded in the directory record area by incrementing the append flag. In this manner, the files which have the same file name and the different append flags are treated as one file having the data recorded in the order of the append flags.
When a file name of the file having the plurality of partial files is to be changed, the erasure directory is first recorded, and as many directories including the new file name as the number of the partial files are recorded.
Because the optical card is of the same size as the credit card and hence easy to carry, the application of the optical card to the addition of data such as recording of daily blood pressure measurement is highly expected. When the file name in the optical card applied to such addition of data is to be changed in the manner described above, it may be required to record several tens to several hundreds of directories. Thus, a long time is required to change the file name and the record capacity for the data is reduced because many directories are recorded.